title: Mismatch repair in Escherichia coli cells lacking single-strand exonucleases ExoI, ExoVII, and RecJ.
abstract: In vitro, the methyl-directed mismatch repair system of Escherichia coli requires the single-strand exonuclease activity of either ExoI, ExoVII, or RecJ and possibly a fourth, unknown single-strand exonuclease. We have created the first precise null mutations in genes encoding ExoI and ExoVII and find that cells lacking these nucleases and RecJ perform mismatch repair in vivo normally such that triple-null mutants display normal mutation rates. ExoI, ExoVII, and RecJ are either redundant with another function(s) or are unnecessary for mismatch repair in vivo.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Canada.
authors.forename: R S
authors.initials: RS
authors.lastname: Harris
authors.forename: K J
authors.initials: KJ
authors.lastname: Ross
authors.forename: M J
authors.initials: MJ
authors.lastname: Lombardo
authors.forename: S M
authors.initials: SM
authors.lastname: Rosenberg
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins; D005090:Exodeoxyribonucleases / Q000172:deficiency* / Q000235:genetics; D016296:Mutagenesis
chemical_list: D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; D005090:Exodeoxyribonucleases; C489467:RecJ protein, E coli; C070765:recJ protein, Bacteria; C028450:exodeoxyribonuclease I; C026870:exodeoxyribonuclease VII